findIndex 返回未定义而不是数字

Question

I have the following code:

const index = myArray.findIndex(
      (f) =>
        f.name === term1 ||
        f.name === term2
    );

As I am trying to debug in Chrome Dev Tools, if I set a breakpoint after this snippet, index always shows as undefined . It was my understanding that findIndex should always return a number , the first index of the array where the condition is met, -1 if it is never met.

If I break immediately after this code and use the console to manually type in the code but don't assign it to anything, the console shows the correct index number. The issue isn't with the item being found in the array. It is there, but in the debugger it will only show undefined.

Why is this code returning undefined rather than a number ?

*I have tried this in Firefox and Edge. It is the same issue there as well.

Answer 1

Just expanding your code a bit I have:-

const term1 = 'aaa';
const term2 = 'bbb';
const myArray = [ { name: 'ccc' }, { name: 'ddd' }, ];
const index = myArray.findIndex(
  (f) =>
    f.name === term1 ||
    f.name === term2
);
console.log(index);

I always get the expected output of -1, or as expected. I tried fiddling with various combinations and types - no go.

In my environment your code works fine - so I would guess the problem lies elsewhere.

Sorry - this doesn't constitute an answer - just some input:-)